The purpose of this study is to measure cerebral blood flow with positron emission tomography (PET) and H2150 (while subjects are listening to scripts about their own traumatic childhood events) in patients with childhood abuse-related posttraumatic stress disorder (PTSD) and subjects with a history of abuse but without PTSD. We hypothesize that exposure to traumatic reminders, in the form of listening to recordings of the subjects own childhood traumatic memories, in the PTSD patients will be associated with an increase in blood flow in the amygdala, hippocampus, parahippocampus, cingulate, medial orbital cortex, basal ganglia, thalamus, inferior parietal cortex, extrastriate cortex (visual association cortex) and temporal cortex, in comparison to blood flow during exposure to neutral recordings and in comparison to blood flow in healthy subjects during exposure to trauma-related recordings.